Arc’s chime is mechanical. A small striker hits a resonant metal bar. No speaker, no digital tone. That distinction matters more than you might expect. Why does it sound so different from a phone alarm? And what do you actually gain from that difference? Let's get into it.

How Loud Is It?

Would Arc’s alarm actually wake you up? We compared Arc against two iPhone alarms — Radial, the default alarm tone, and Radar Classic, one of the loudest options available.

There are two measurements worth paying attention to here. The average level tells you how loud the sound is over time. The peak level tells you the loudest instant the alarm reaches.

Arc sits directly between the two iPhone alarms. It’s louder than the default Radial alarm, but less extreme than Radar Classic, whose peak crosses 102 decibels. That placement was intentional. We wanted to make sure Arc could wake you up without being as jarring as many smartphone alarms.

But volume isn’t the whole story.

These measurements tell you how much sound energy each alarm produces. They don’t tell you what kind of sound it is. A loud low tone and a loud high-pitched screech can register similarly on a decibel meter — but they feel completely different when you’re trying to wake up.

The frequency an alarm emphasizes matters just as much as how loud it is.

Radar Classic concentrates much of its energy around 2,700 Hz, near the upper range where sounds tend to feel sharp and urgent. Arc’s chime centers around 493 Hz — roughly the note B4 on a piano. Lower, rounder, and very different in how it fills a room.

Why Arc Sounds Richer

What most people notice when they hear Arc in person isn’t the volume. It’s the character of the sound. A struck metal bar doesn’t produce a single tone. It produces a complex set of frequencies called overtones.

Above is a finite element simulation of Arc’s chime bar. Each panel shows a different natural vibration mode of the metal bar when struck. The colors represent how much each part of the bar moves (red = most motion, blue = least). The ~493 Hz mode produces the fundamental pitch of the chime, while the higher modes create the overtones that give the sound its richness.

These harmonics are what give bells, chimes, and acoustic instruments their character. During development, we tuned the geometry and material of Arc’s chime bar to produce a balanced set of these overtones.

A mechanical chime doesn’t stop abruptly. But the other important difference is how the sound fades.

When the striker hits the bar, the sound starts loud and then gradually fades as the metal’s vibrations dissipate into the surrounding air and structure. On the Arc graph, you can see this clearly: one strike, followed by a smooth downward slope. Within a few seconds the sound has naturally decayed.

A digital alarm works differently. There’s no physical object vibrating in the room. Instead, the alarm plays a recorded sound file through a speaker.

You can see this clearly in both iPhone panels — the sound doesn’t decay naturally, it repeats. Radar cuts on and off sharply. Radial pulses more gradually, but it’s still the same pattern looping every few seconds until you turn it off.

That difference is part of why people often describe Arc as sounding less jarring, even at comparable volumes. A sound that fades naturally feels like it belongs in the physical world. A sound that repeats indefinitely is designed to demand your attention — because it is.

One More Difference

There’s one other difference worth mentioning. When your alarm lives inside your phone, the device that wakes you up is also the device that holds your notifications, messages, and an endless stream of information competing for your attention.

A dedicated alarm clock changes that relationship. The object by your bedside has a single job: waking you up. For some people that means less blue light before bed. For others it means fewer notifications waiting first thing in the morning.